MODIFICATIONS OF OXYGEN-SATURATION DURING TRANSESOPHAGEAL ECHOCARDIOGRAPHY

The present study was designed: (1) to establish the effects of transe sophageal echocardiography (TEE) on arterial oxygen saturation (SAO(2) %); (2) to verify the possible clinical consequences of this phenomeno n; and (3) to study the possibility of predicting modifications of SAO (2)% by clinical or hemodynamic variables or by specific factors relat ed to the TEE procedure. We prospectively studied 116 unselected patie nts, aged 61 +/- 12 years, who underwent diagnostic TEE for various cl inical indications. Thirty-seven patients had mitral value disease, 19 aortic valve disease, 14 combined mitroaortic disease, 8 congenital h eart disease, and 38 other cardiovascular diseases. Eight patients wer e affected by chronic obstructive pulmonary disease. Ninety-seven pati ents were sedated by 4 +/- 2 mg of diazepam IV SAO(2)% (5-min average) (Ohmeda Biox 3700 pulse oxymeter finger probe), heart rate (HR), and blood pressure (BP) were considered during baseline; transthoracic exa mination, after pharmacological sedation but before the introduction o f the probe, and finally during TEE. Neither clinical complications no r major arrhythmias were observed. Baseline SAO(2)%, HR and BP were, r espectively, 93.6 +/- 3.3%, 76 +/- 14 beats/min, and 129 +/- 20/75 +/- 10 mmHg. Pharmacological sedation did not modify SAO(2)%, HR, and BP (P > 0.1). During TEE a small but significant reduction in SAO(2)% by an average of 1.2 +/- 3.2% was observed (P < 0.005), as well as a smal l and significant increase in HR by an average of 3 +/- 10 beats/min ( P < 0.01). BP did not change significantly (P > 0.1 for both systolic and diastolic). The changes of SAO(2)% and HR were not interrelated an d were not related to the duration of the procedure and to any of the clinical and hemodynamic variables taken into consideration. TEE can i nduce a small but significant drop in SAO(2)% and a small increase in HR even without any clinical relevance. No clinical or hemodynamic var iable or specific factors related to the TEE procedure were related to these changes.